Exhaust valve assemblies include a flapper valve that is supported on a shaft within an exhaust tube. An actuator, mounted externally to the flapper valve, drives the shaft to move the flapper valve within the exhaust tube to control exhaust flow. Actuators can include electric actuators such as motors or solenoids, or vacuum actuators, for example.
Each type of actuator has an operating temperature limitation. Exhaust gases that flow through the exhaust tube can reach very high temperature levels. Disadvantageously, these high temperatures can be transferred to the actuator via the shaft, which can adversely affect operation of the actuator.
One proposed solution has been to extend a length of the shaft to reduce the temperature at the actuator. However, increasing shaft length makes the overall packaging of the exhaust valve assembly more complex and bulky, which is not desirable. Further, this drives up the cost for an exhaust valve assembly in order to accommodate temperature limitations of the actuator.
Thus, there is a need for an improved exhaust valve assembly that reduces heat transfer from a valve to an actuator, while additionally providing a more flexible and compact design configuration.